Black "Soot" on Furnace Filter

I live in a 1989 manufactured home. The furnace (gas, forced air) is the original unit. I have been pretty good about cleaning the filter regularly (it's a reusable allergy filter) - it's been dirty before, but this time it was completely black. We've been tackling a pilot light issue for years - whenever it's windy outside, the pilot blows out. So I've had the front covers off about once or twice a week over the last month and the filter wasn't black at all the last time I had it off. (Before you chime in on this problem, let me just say we've had several different HVAC contractors out to look at it. One of them installed the "fix" recommended by Coleman, but no luck. But - - that's another thread.)

I don't know if this is relevant, but I discovered a rotted section of siding two weeks ago - roughly a 4' x 4' area of pressboard siding, also carpet and drywall and in between needs to be replaced. The affected padding and drywall has been removed. A fan was used to dry the area and we're about to start the repairs.

Someoone suggested it may be black mold on the furnace filter. Does anyone know if this is a possibility? Or what else may be the problem causing the sudden black sooty mess in my furnace filter?

Not visibly, no. I did spray some bleach solution on it already, then put a fan up. But it still has that moldy smell - the siding and framing is still damp, and it's all exposed until the guy gets out here to fix it.

I didn't spray the inside of the siding too much, since it was going to come out anyway, (figured it would be out by now, but there were other jobs ahead of us). I'll spray everything really good again.

If you are getting Soot on the Filter, I would be checking Co levels before anything else. When you brush the filter with you hand, is there Soot coming off of it onto your fingers, or does the coloration stay on the media?

Then you have problems, and it is more then the mold. Do you even have a CO detector in the house? If not, get one now, and have the system checked out. Also, is there black soot in the Intake chamber of the Furnace (where the blower motor sits)?

gas furnaces do not produce black soot,that would be oil.did you notice any black soot in your house around the supplies?Do you burn alot of candles?you can get a mold kit at home depot and mail it out for like 10.00 bucks,never used one,just a thought.I would try and get a throw away filter,the pleated kind and see what kind of results you get from that.if your filter is old it might be time for a new one.where di you take your co2 readings?